1. Technical Field
The present disclosure relates to a radar apparatus and a target object detection method in which objects existing nearby may be detected without false detection with use of results of measurement by the radar apparatus.
2. Description of the Related Art
In recent years, vehicles in which radar apparatuses that detect other vehicles, pedestrians, bicycles, motorcycles, or installations on roads existing around the vehicles are installed have been increasing. An in-vehicle radar apparatus detects an object coming nearer from front or a side of a host vehicle and measures a relative position of the object with respect to the host vehicle or a relative velocity of the object with respect to the host vehicle. The in-vehicle radar apparatus determines whether there is a possibility of a collision between the host vehicle and the object, based on results of such measurement. In a case where the radar apparatus determines that there is the possibility, the radar apparatus gives a driver a warning or avoids the collision by controlling driving of the host vehicle.
Meanwhile, systems have been developed that monitor or manage road traffic with use of radar apparatuses installed adjacent to roads. The systems detects vehicles or pedestrians passing through intersections, by radar apparatuses installed adjacent to the intersections, for instance, or adaptively controls traffic lights by measuring traffic flow. In a case where the systems determines that there is a possibility of a collision among a plurality of objects, such as a vehicle and a pedestrian, on a road, the system gives drivers and/or pedestrians warnings and tries to avoid the collision among the plurality of objects.
As another method of utilizing radar apparatuses, there is an example in which radar apparatuses are installed in order to monitor an airport or other facilities, for instance. Such radar apparatuses detect objects coming from sky or on ground, provide information on the objects to associated security systems, and thereby check intrusions of the objects.
Thus radar apparatuses are used in order to detect objects in various situations. When particulate obstacles exist around the radar apparatuses, for instance, in conditions of rainfall or snowfall or environments where mist, dust, sand, withered leaves, or the like exists, however, detection accuracy for the objects is decreased by undesired reflection echoes from such particulates. As technology to deal with such situations, Japanese Unexamined Patent Application Publication No. 2008-170323 discloses technology that improves the detection accuracy for a target object in the conditions of rainfall or snowfall by extending integrating time for radar signals in comparison with that in conditions of non-rainfall or non-snowfall.